dvd recorders - most do either +r and +rw discs or -r and -rw discs, not a huge difference between minus and plus as regards compatiblity if you want to use the recorded disc in another dvd player. Other type is DVD Ram - which I think gives the best features - like pausing live tv and simultaneous record one program while watching another. - But, Ram discs will only play in Ram players/recorders, so try to get a DVD recorder that supports DVD Ram and (-r/-rw) or (+r/+rw)
As regards NTSC and PAL signals , you probably will run into trouble trying to send the NTSC signal into the PAL machine - but you can buy NTSC to PAL converters - check out Ebay or Maplin electronics.